Brian Howey is a conformist.

I. Skin

A. Anatomy 1. 3 Layers: Epidermis, Dermis and

Subcutaneous/Hypodermis (not part of skin).

2. Melanocytes: Cells within the dermis that produce melanin.

3. Keratinocytes: Cells within the dermis that produce keratin, the major protein in skin

I. Skin

B. Physiology

1. Makes vitamin D

2. Protection: Strong due to collogen

component.

3. Temperature Regulation

II. Bone

A. Osteocytes: Bone cells

1. Osteoblasts: Build Bone Tissue

2. Osteoclasts: Dissolve Bone Tissue

B. Osteon: Functional Unit of Bone Building.

II. Bone

C. Anatomy: Compact bone, Spongy bone, Yellow Marrow, Red Marrow

1. Compact: Lacks air spaces

2. Spongy: Interlaced with air spaces

3. Yellow Marrow: Stores fat

4. Red Marrow: Produces blood cells.

III. Muscle Contraction

A. Sarcomere: Functional unit of muscle contraction.

1. Actin – Thin protein filaments

2. Myosin - Thicker protein filament

Fig. 38.20c, p. 658

one actinmolecule

part of a thin filament

Arrangement of actin molecules in the thin filaments of a sarcomere

parts ofmyosinmolecule

part of a thick filament

Arrangement of myosin molecules in the thick filaments of a sarcomere

Muscle Contraction

B. Sliding Filament Theory: The myosin proteins slide past the actin filaments.

Pulls Z-bands closer together.

Fig. 38.21, p. 659

Cross-bridgeforms betweenan actin and a myosin filament

Actin filamentslides past myosinfilament, towardsarcomere’scenter, in apower stroke

The cross bridge is broken

Another cross-bridge formsbetween samefilaments

Another powerstroke slides actinfilament closerto the center ofsarcomere

sarcomerebetweencontractions

actin myosin actin

samesarcomerecontracted

IV. Signaling Muscle Contraction

A. Motor neurons stimulate release of

calcium for muscle contraction.

B. Calcium provided by Sarcoplasmic Reticulum.

C. Acetylcholine is neurotransmitter that communicates with muscle.

Fig. 38.23, p. 660,61

section from spinal chord

motorneuron

Signal from the neuronsystem travel along spinalcord, down motor neuron

T tubule

section from a skeletal muscle

Sarcoplasmic reticulum(calcium storage)

plasmamembraneof skeletalmuscle cell

Z band Z band

one of themyofibrilsinside themuscle cell

IV. Fueling Muscle Contraction

A. When myosin and actin interact, they

need ATP to release.

B. Preference for ATP: Creatine Phosphate, Respiration, then Lactic Acid Fermentation